The present application is a U.S. non-provisional application based upon and claiming priority from Russian Application No. 2002103668, with a filing date of Feb. 8, 2002, which is hereby incorporated by reference.
This invention relates to the area of chemistry and petrochemistry, more precisely to a process for producing p-cumylphenol (PCP) by means of catalytic alkylation of phenol with xcex1-methylstyrene (AMS).
p-Cumylphenol is widely used in producing effective stabilizers for fuels, oils, polymers, and rubbers.
Processes are known for producing p-cumylphenol using homogeneous acidic catalysts, such as strong mineral acids: sulfuric, oxalic, phosphoric, etc. [a) Kumok, Gurvich, Stiskin, Grinberg. Zh. Vses. Khim. Obshchestva im. Mendeleeva 17:4.460-462 (1972); b) U.S. Pat. No. 2,444,1408 (1948); c) U.S. Pat. No. 2,751,437 (1950)]. The disadvantages of this process are typical for the use of homogeneous catalysts. These are the low selectivity of the process, the difficulty of separating the catalytic complex from the reaction products, and ecological problems connected with the use of strong acids.
The indicated disadvantages are not present in the process for producing p-cumylphenol which uses heterogeneous catalysts, for example based on synthetic zeolites of the type of dealuminated mordenite or zeolites of the ZSM family, which are prepared with or without a binder and with the addition of promoter metals or without additives [U.S. Pat. No. 4,409,412 (1982)]. The disadvantage of using catalysts of this type is their insufficient activity and increased formation of side products. For example, when PCP is made by this method, dimer side products are also produced. Specifically, when this reaction is carried out at a temperature of 100xc2x0 C., a raw material volumetric feed rate of 1 hxe2x88x921, using dealuminated mordenite as the catalyst, the content of the end product PCP in the catalysis product is 12-13% by mass, with the dimer content being greater than 4% and the o-cumylphenol content being 0.5-0.7% (wherein the diner and o-cumylphenol content is greater than 4.5%). When a sample of TsVM zeolite (a member of the ZSM-5 family) is used as catalyst quality of end product PCP is 11-12%, the dimer content is 0.6-0.7%, the o-cumylphenol content is about 2.2%, and the total content of dimer and o-cumylphenol is greater than 2.8%. (more than 2.8%), respectively.
In another known process for producing PCP, an ion-exchange resin of the type of Amberlyst in the hydrogen form is used as the catalyst [U.S. Pat. No. 5,185,475 (1993) prototype].
At a temperature of 80-110xc2x0 C., under atmospheric pressure, and with a raw material volume feed rate of 1.0 hxe2x88x921, the content of PCP in the catalysis product is 16.2-16.5%, the content of dimers is around 0.3-0.5%, and the content of o-cumylphenol is 4.4% (the total of the latter two is greater than 4.6%). The disadvantages of the PCP synthesis process using ion-exchange resins as catalyst which is proposed as a prototype are as follows:
increased content of side products (o-cumylphenol and dimers);
insufficient activity of the catalyst;
low thermal stability of the catalyst, lowering its service life;
difficulty of regenerating the catalyst;
necessity of additional purification of the reaction products on alkaline sorbents to remove acidic components which are washed out of the catalyst.
The goal of this invention is to increase the activity and selectivity and to simplify the technology of the process for producing p-cumylphenol.
The indicated goal is achieved by alkylating phenol with xcex1-methylstyrene using a heterogeneous acidic aluminum zirconium catalyst at a temperature of 80-110xc2x0 C. Also, a relative raw material volumetric feed rate must be maintained through the catalyst bed as necessary to provide a space velocity of 1-3 hxe2x88x921 (hereinafter referred to as a xe2x80x9cvolume feed ratexe2x80x9d).
The catalyst represents a mixture of aluminum oxide and zirconium oxide promoted by sulfate, with the total content of aluminum and zirconium sulfates being from 5 to 15% by mass (calculated on the basis of SO4 ions) and the total content of aluminum oxide and sulfate being 5-30% by mass (calculated on the basis of Al2O3).